Helium is the key to shrinking microchips, according to physicists from Indiana University and the University of Tennessee.
Paul Sokol. Image Credit: Photo by Indiana University.
Microchips are used in everything now, from computers and automobiles to helping people recover their missing pets. As microchips become, faster, smaller and capable of doing more things, the wires that conduct electricity to them must follow suit. But unless they are created differently, they can only become physically small.
In a traditional system, as you put more transistors on, the wires get smaller. But under newly designed systems, it’s like confining the electrons in a one-dimensional tube, and that behavior is quite different from a regular wire.
Paul Sokol, Professor, Department of Physics, Bloomington College of Arts and Sciences, Indiana University
Sokol and Adrian Del Maestro, a professor of physics at the University of Tennessee, worked together to build a model system of electronics packed inside a one-dimensional tube in order to explore the behavior of particles under these conditions.
A recent publication of their findings in Nature Communications.
Helium was chosen by the pair as a model system for their research because of its well-known interactions with electrons and the ease with which it can be made incredibly pure, according to Sokol. But, there were challenges when it came to using helium in a one-dimensional space, especially considering that no one had ever done it before.
Think of it like an auditorium, people can move around in lots of different ways. But in a long, narrow hall, nobody can move past anyone else, so that behavior becomes different. We're exploring that behavior where everyone is confined in a row. The big advantage of using a helium model is that we can go from having very few people in the hall to having it packed. We can explore the entire range of physics with this system, which no other system lets us do.
Paul Sokol, Professor, Department of Physics, Bloomington College of Arts and Sciences, Indiana University
The researchers also faced several other difficulties in developing a one-dimensional helium model system. For instance, it was too challenging to take measurements if they attempted to create a tube tiny enough to store the helium.
Additionally, it was not able to apply methods like neutron scattering, a potent technique that uses a reactor or accelerator to produce a beam of neutrons in order to collect comprehensive data on particle behavior in a one-dimensional system.
On the other hand, using specialized glasses built around template molecules, scientists could create incredibly long tubes, but the holes were not large enough to contain the helium in one dimension.
You literally need to make a pipe that is only a few atoms wide. No normal liquid would ever flow through such a narrow pipe, as friction would prevent it.
Adrian Del Maestro, Professor, Department of Physics, University of Tennessee
The scientists used one-dimensional channel glasses that had been coated with argon to create a narrower channel and nano-engineered a material to address this problem. Then, scientists could create samples that could potentially enable the application of methods like neutron scattering to obtain in-depth knowledge about the system and contain a lot of helium.
Del Maestro and Sokol have created a significant new path for this study with their experimental realization of one-dimensional helium.
The team intends to explore helium at low concentrations, comparable to one-dimensional arrays of atoms employed in quantum information science, and high densities, comparable to electrons in a thin wire, using this novel model system.
The researchers also intend to create additional nanoengineered materials, such as pores covered with cesium where the helium does not wet the surface of the cesium. This would make the contained helium even less likely to interact with the outside environment and create a system that is more suited for testing novel hypotheses.
Journal Reference:
Maestro, A. D., et al. (2022) Experimental realization of one dimensional helium. Nature Communications. doi.org/10.1038/s41467-022-30752-3.